Mini-test dish

ABSTRACT

A method and apparatus for multiple test cultures having an open-topped container and a cover forming a dust-proof enclosure therewith. The container is partly filled with a culture supporting medium and a dividing member is inserted therein to divide the medium into plural open-topped test areas of equal volume. Cultures are then introduced into the various test areas to provide simultaneous multiple tests in the same support medium.

United States Patent [191 Farmer, III

[ Feb.6, 1973 1 1 MINI-TEST DISH [75] Inventor: John J. Farmer, lll,Bethesda, Md.

[73] Assignee: The United States of America as Represented by theSecretary of the Department of Health, Education and Welfare.

[21] App1.No.: 54,738

[52] U.S. Cl. ..195/103.5, 195/140, 229/15, 220/221 [51] Int. Cl. ..Cl2kl/00 [58] Field of Search; ..195/127, 139, 139 LE, 140, 195/103.5;217/22, 30; 229/15, 29 D, 29 M, 28; 206/65, 65 E, 65 Y; 220/22, 22.]

[56] References Cited UNITED STATES PATENTS 2,874,091 2/1959 Fisk..195/139 3,272,719 9/1966 Avakian ..l95/139 3,197,384 7/1965 Goldman 73,036,726 5/1962 I Wilkins ..217/22 3,383,027 5/1968 Brinkama et a1...229/15 FOREIGN PATENTS OR APPLICATIONS 218,386 11/1958 Australia..217/30 Primary Examiner-A. Louis Monacell Assistant Examiner-Robert M.Elliott Attorney-John S. Roberts, Jr. and Norman J. Latker [5 7]ABSTRACT A method and apparatus for multiple test cultures having anopen-topped container and a cover forming a dust-proof enclosuretherewith. The container is partly filled with a culture supportingmedium and a dividing member is inserted therein to divide the mediuminto plural open-topped test areas of equal volume. Cultures are thenintroduced into the various test areas to provide simultaneous multipletests in the same support medium.

4 Claims, 2 Drawing Figures i llmlllll n" PATENTEDFEB ms 3.715.280

INVENTOR JOHN J. FARMERIH ATTORNEY MINI-TEST msn BACKGROUND OF THEINVENTION In diagnostic and bacteriological laboratories, the

classification of bacteria and certain other microorganisms is usuallybased on their biochemical properties.

In the routine testing and identification of unknown strains, it isnecessary to make multiple tests to determine such properties as: acidproduction from fermentation of carbohydrates; growth using certainknown compounds as energy sources; the production of extracellularenzymes; vitamin, amino acid and other nutritional requirements;inhibition by antibiotics and other chemicals; pigment production onvarious media; biochemical changes brought about by specific enzymes;and growth at various pI-Is.

It is common in the present art to conduct such tests in individualtubes supplied by manufacturers with the required media, ready for asingle test. Such apparatus has proved to be greatly beneficial tolaboratories due to the savings in preparation time and materialrequired to conduct these multiple tests. The costs involved, however,are excessive in that the individual tubes and the time and carerequired in preparation thereof impose high production costs on themanufacturer.

Petri or culture containing dishes having compartmentalized interiorsare also available for conducting the multiple testing described above.Such compartmentalized dishes offer advantages in material cost over theindividual tubes; however, each compartment must be filled individuallywith warm media which, even with automatic pipetting devices, is a timeconsuming step. Where more than one medium is to be used in filling thedish, a separate filling device must be used for each medium and it isdifficult and time consuming to provide a consistent proportion of mediain each compartment.

SUMMARY OF THE INVENTION This invention provides a multiple test dishtype culture container which overcomes the disadvantages of the priorart by furnishing a container which is filled with the culturesupporting medium which is subsequently divided into separate and equaltest volumes within the container.

The invention also provides a multiple test culture container in whichplural test cultures of equal volume and constant composition are easilyand quickly provided by furnishing a device in which the support mediumis composed as a whole in a container and subsequently divided, in situ,into separate and equal test volumes by insertion of a divider comprisedof sets of intersecting, parallel, equally spaced dividing walls.

In a preferred embodiment, the invention comprises an open toppedcontainer or tray having a bottom and substantially vertical side walls;a divider member including intersecting sets of equally spaced,uninterrupted, parallel walls of less vertical extent than the extent ofthe container side walls and configured or so dimensioned relative tothe container or tray as to be removably disposed in the container tofit closely with the walls thereof and divide the interior into plural,open-topped compartments of equal volume; and a cover member configuredto engage the upper edges of the side walls to form a substantiallyairtight enclosure with the container.

These and other objects and many of the attendant advantages of thisinvention will become better understood to those skilled in the art byreference to the following detailed description when viewed in light ofthe accompanying drawing wherein like components throughout the FIGURESthereof are indicated by like numerals and wherein:

BRIEF DESCRIPTION OF THE DRAWINGS FIG, 1 is an exploded perspective viewof a device in accordance with the invention; and

FIG. 2 is a view similar to FIG. 1 showing a portion of the device in anassembled, in-use configuration.

DESCRIPTION OF THE PREFERRED EMBODIMENT In FIG. 1, the device isillustrated and is comprised of three major portions, generallyindicated as an open topped container 10, a dividing member 12 and acover member 14. I

The container 10 is provided with substantially vertical side walls 16and a bottom 18 which define a square, substantially sharp-cornered box.The dividing member 12 is comprised of two sets of equally spacedparallel walls 20 and 22 which intersect one another at right angles.The dividing member is configured to fit snugly within the confines ofthe container 10 such that the interior of the container is divided intocompartments of equal volume by the intersection of the dividing member12 and by the peripheral portion of the dividing member and the walls 16of the container. It is important that the compartments formed by thedivider be substantially equal in volume in order to maintain constantrelationships in tests conducted in the various compartments. In thisrespect, the verticallity of the walls 16 is important in that theperipheral compartments would be of different volume than the interiorcompartments if their orientation were other than vertical.

The cover 14 is composed of an upper wall 24 and depending edge walls26. The lower edge or horizontally extending continuous shoulder of thewalls 26 is provided with a lip 28 which fits snugly against the innersurfaces of the side walls 16 of the container 10 to thereby provide asubstantially airtight relationship between the container and the cover14 when the components are joined In other words, the closure or coverhas a closed top and the depending edge or side walls include the lip 28that constitutes a depending, continuous, uninterrupted side wallportion having external dimensions and an external configuration sorelated to the internal dimensions and configuration of the verticalside walls 16 of the tray as to closely fit therewith to isolate thecompartments of test areas from contamination by ambient conditions,

The above-described components are preferably fabricated of a plasticwhich is compatible with the use environments and which can besterilized by ethylene oxide, for example. If the plastic used isthermostable, the device could be autoclavable and re-usable.

Although the device can be fabricated in any size and capacity desired,a device having container dimensions by 160 mm. and a height of 15 mm.has been found to be particularly suitable for the purposes of thisinvention. Such a container has a cover 14 which is by 165 mm. and mm.in height with a divider 12 which is 12 mm. in height and having walls22 on the order, for example, of 0.5 to 2 mm. in thickness. With sets ofsix equally spaced walls in each direction, 49 equal and squarecompartments mm. on each side are formed within the container 12.

In operation, bacteriological test agar or semisolid agar is sterilizedand cooled to between 45 and 50. A layer 29, approximately 7 mm. inthickness, is aseptically poured into the container 10 and, referringnow to FIG. 2, while the agar 29 is still warm or in the semisolidcondition, the divider 12 is lifted with sterile forceps and is fullyinserted to divide the agar into plural test areas 30. The unit is thencooled, preferably aseptically by air passed through filters such as ina laminarflow cabinet, to cool and solidify the agar in the test areas30 into a hard gel.

Many of the tests now performed in liquid media could be-adapted to a1.5 percent agar or semisolid medium and then performed in the device ofthis invention. By having the tests confined by the walls 22 of thedivider l2, diffusable substances suchas acids, alkali, enzymes, smallmolecules, etc., precluded from interfering with tests performed inadjacent test areas 30.

When the device is prepared, the cultures and/or materials to be testedare deposited in individual test areas and the cover 14 is emplaced toas mentioned previously, isolate the tests from contamination by ambientconditions.

With a device of the above dimensions, 49 individual tubes of the priorart are replaced and the resultant material costs of the tests arereduced by 90 percent. The reduction in labor time, costs and improvedconsistency over the prior art permanently divided dish described aboveare obvious.

Although the device has been specifically described above as beingrectangular, the container 10 and cover 14 could, within the scope ofthe invention, be circular or otherwise shaped. In the event thecontainer is circular, the dividing member 12 could be comprised of aplurality of radially extending walls intersected by annular, coaxialwalls such that the plurality of compartments of equal area are formedthereby.

What is set forth above is exemplary of a teaching in accordance withthe invention to enable those skilled in v the art in the practicethereof.

l. The method of conducting a multiple test culture comprising the stepsof pouring a layer of semisolid culture media at a temperature ofapproximately 45-50C into a sterilized open-topped container,maintaining the temperature of said media, inserting a sterilizeddividing member comprising intersecting sets of equally spaced parallelwalls into said container to divide said media into plural individualtest areas, cooling said media in a sterile environment to providegelling thereof, depositing test material into the various test areas toconduct simultaneous separate tests thereof, and covering said containerto render the interior thereof substantially airtight.

2. A test assembly for facilitating multiple testing of biochemicalproperties of microorganisms, in diagnostic and bacteriolo icallaboratories embodying three components of p astic material compatiblewit the environment of testing usage and sterilizable to be closedbottom and a continuous, uninterrupted substantially vertical side wallportion; a divider member including cooperative intersecting sets ofequally spaced uninterrupted divider walls defining interstices ofsubstantially equal cross-sectional area, said divider walls having lessvertical extent than the extent of said vertical side wall portion, saiddivider member being so dimensioned relative to said tray as to beremovably insertable within said side wall portion in a close-fitrelationship to define therewith and within said tray a plurality ofopen-topped compartments of equal volume adapted to confine a layer ofculture supporting medium into a like plurality of individual equalvolume test areas for receiving test material; and a closure including aclosed top and at least a depending, continuous, uninterrupted side wallportion having external dimensions and an external configuration sorelated to the internal dimensions and configuration of said verticalside wall portion of said tray as to closely fit therewith to isolatesuch test areas from contamination by ambient conditions.

3. A test assembly as claimed in claim 2 in which said vertical sidewall portions having an upper edge portion and said closure furtherincluding a horizontally extending continuous shoulder adapted to engagesaid upper edge portion.

4. A test assembly as claimed in claim 2 in which said tray isrectangular, said divider walls of each set being parallel, and saidsets of divider walls intersecting one another at approximately

1. The method of conducting a multiple test culture comprising the stepsof pouring a layer of semisolid culture media at a temperature ofapproximately 45*-50*C into a sterilized open-topped container,maintaining the temperature of said media, inserting a sterilizeddividing member comprising intersecting sets of equally spaced parallelwalls into said container to divide said media into plural individualtest areas, cooling said media in a sterile environment to providegelling thereof, depositing test material into the various test areas toconduct simultaneous separate tests thereof, and covering said containerto render the interior thereof substantially airtight.
 2. A testassembly for facilitating multiple testing of biochemical properties ofmicroorganisms, in diagnostic and bacteriological laboratories embodyingthree components of plastic material compatible with the environment oftesting usage and sterilizable to be reusable; said componentscomprising a tray having a closed bottom and a continuous, uninterruptedsubstantially vertical side wall portion; a divider member includingcooperative intersecting sets of equally spaced uninterrupted dividerwalls defining interstices of substantially equal cross-sectional area,said divider walls having less vertical extent than the extent of saidvertical side wall portion, said divider member being so dimensionedrelative to said tray as to be removably insertable within said sidewall portion in a close-fit relationship to define therewith and withinsaid tray a plurality of open-topped compartments of equal volumeadapted to confine a layer of culture supporting medium into a likeplurality of individual equal volume test areas for receiving testmaterial; and a closure including a closed top and at least a depending,continuous, uninterrupted side wall portion having external dimensionsand an external configuration so related to the internal dimensions anDconfiguration of said vertical side wall portion of said tray as toclosely fit therewith to isolate such test areas from contamination byambient conditions.
 3. A test assembly as claimed in claim 2 in whichsaid vertical side wall portions having an upper edge portion and saidclosure further including a horizontally extending continuous shoulderadapted to engage said upper edge portion.